I get a REALLY slow speed due to distance. (0.7mbs.) Does anyone out there use Mobile Braodband to game? Is it any good, The providers seem to suggest speeds upto 20Mb is that true?
Also do I have to worry about download ammount during a normal month of gaming.

I expect you wouldn't have too many issues speed wise (although don't expect anything like 20mb unless you are in an area where you can get a solid 3g signal on a phone). However you might run into issues with any data cap and should look for 5gb per month to be sure you won't get overage charges.

For an MMO it might not matter all that much but for an fps it might be a really bad thing.
I had IP-TV (on my adsl) for a while and it was bad even playing MMOs as the ping got worse when the link was tuned for both data and IP-TV. Doing just a ping to my base station didnt show that bad numbers but it was enough. Think I went from 10ms to 40ms but my memory might play tricks.